Oregon health insurance lottery shows access to insurance increases health care use; improves well-being, decreases financial strain

July 7, 2011

The first results of the 2008 Oregon health insurance lottery study, supported in part by the NIA, indicate that people enrolled in the state’s Medicaid program reported improved health and well-being, as well as reduced financial strain. They also saw an increase in use of primary and preventive care as well as hospitalizations. Program expenditures rose as a result of the rise in utilization. The study results were reported in a National Bureau of Economic Research (NBER) Working Paper, in a collaboration between NBER researchers and the state of Oregon.

The Oregon program randomly assigned 10,000 low-income uninsured adults to the state’s Medicaid program. Participants were chosen from about 90,000 people who signed up for the lottery program. After 1 year, the study found that enrollment in Medicaid increased the likelihood of using outpatient care by 35 percent, using prescription drugs by 15 percent, and having a regular office or clinic for primary health care by 70 percent among those with insurance. The probability of having an unpaid medical bill sent to a collection agency decreased by 25 percent among those in the program. The probability of people reporting themselves in good to excellent health (compared with fair or poor health) increased by 25 percent among those with insurance. The increased use of health care services resulted in an estimated 25 percent increase in annual health care expenditures.

The researchers note that these findings are part of a broader study that will continue to follow the participants in the program. Ongoing work will provide more information on the effects of expanded insurance, including specific clinical indicators and health outcomes measured over 2 years; the current study covers the first year of the lottery. Together, this information will facilitate the evaluation of costs and benefits of insurance expansions.


Finkelstein, A., et al. The Oregon Health Insurance Experiment: Evidence from the First Year, NBER Working Paper 17190, National Bureau of Economic Research, Cambridge, Mass., July 7, 2011.

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